HP 3000 Manuals HP 3000 Manuals
GLOSSARY
Data Universal
An initialized data symbol defined in an object module that is visible
(exportable) to other object modules.
Data Unsat
A data symbol that is referenced by an object module but not defined in
it. These symbols are allowed in XLs and program files for shared global
data.
DXRT
A Data Cross Reference Table. The table is initialized by the loader at
run time with data definition addresses. All data references that need a
corresponding definition has an entry in this table. This table is
created by the Link Editor for shared global data support.
Export
A variable or procedure that is defined in a module and sharable with
other modules outside of the one it is defined in. It can be used to
satisfy references (imports).
Global Data
Data definitions, either initialized or uninitialized, that are exported
to or imported from other compilation units.
Import
A reference in a module to a variable or procedure that is defined in
another module. The request (import) can be satisfied by a corresponding
export.
Object File, Object Module
A file, NMOBJ, produced by compilers and used as input to the Link
Editor.
Process Data Dictionary
The Process Data Dictionary (PDD) is the repository of all data symbol
resolution that has taken place on a process. Its main functions are to:
* Maintain information on all resolutions.
* Enforce resolution semantics by controlling the addition of new
symbols. All arbitration between duplicate definitions is done by
the dictionary.
* Maintain information to undo the effects of a failed load.
Shared Global Data
Data definitions, either initialized or uninitialized, that are exported
to or imported from other compilation units. They are sharable with
other modules if they are exportable. That means they are not marked as
hidden and, therefore, ignored by the loader.
Storage Universal
An uninitialized data symbol created when an uninitialized data
declaration is made. If no corresponding Data Universal is found for it
during linking, the scope is changed from Unsat to Universal and the
symbol is exportable and can be used to satisfy references (imports).